Internal-combustion engine



1927 c. F. KETTERING INTERNAL COMBUSTION ENGINE Fi led Nov.

2 Sheets-Sheet l 1927' c. F. KETTERING INTERNAL COMBUSTION ENGINE Filed Nov. '7, 1923 2 Sheets-Sheet 2 Jun ian?" 2g 'MM H1 Eifll 2 0.721 E 275 Patented Oct. 11, 1927.

UNITED STATES PATENT OFFICEQ CHARLES F. KETTERING, OF DAYTON, OHIO, ASSIGNOR TO GENERAL MOTORS BE- SEARCH CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

INTERNAL-COMBUSTION ENGINE.

Application filed November 7, 1923. Serial No. 673,238.

This invention relates to internal-combustion engines having valve mechan1sm of the over-head type, a type of mechanlsm which is generally understood to include one or more rocker arms located adjacent the head of the engine cylinder, and push rods extending along the side of the engine cylinders for operating the rocker arms.

One object of the invention is to compcnsiite for variations in temperature to which the valve mechanism is subjected'so that the clearance between the parts of the valve mechanism will remain substantially constant.

A further object is to provide for adjusting the clearance between the operating parts of a plurality of'valve mechanisms in a simple manner Further objects and ad antages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is'a fragmentary end view of an internal-combustion engine provided wit-h the present invention, a portion being shown in section which is taken on the line 11 of Fizz. 3.

Fig. 2 is a plan view of two engine cylinders provided with valve operating mechanism shown in Fig. 1.

Fig. 3 is a fragmentary side elevation of two engine cylinders provided with the valve operating mechanisms shown in Figs. 1 and 2.

Fig. 4 is a sectional view on line 4--4 of Fig. 2, this view being drawn to a larger scale than the drawings of Figs. 1 and 2.

In the-drawings, the engine crankcase is designated by numeral to which is attached a plurality of engine cylinders 21 provided with cooling fins 22. The cylinders 21 are attached together at their head ends by means of a superstructure 23 which provides separate exhaust pipes 24 for the two cylinders21 and the common intake pipe 25. Each cylinder is provided with two valves, one of which is shown at 26 in Fig. 1. Valve26 includes a stem 27 which is guided by the superstructure 23, and said valve is held closed by means ofa spring 28 which bears. at one end against a washer 29 supported by the superstructure 23 and at the other end against a washer 30 attached to the valve stem 27.

The valve operating mechanism for each valve 26 includes a rocker arm 31 pivoted on a rod 32, and carrying a screw 33 provided with a ball 34 which is received by a socket member carried at the upper end of the push rod 36. The lower end of the push rod 36 is connected with a plate 37 actuated by an engine driven cam 38. Rotation of cam 38 will. cause the push rod 36 to move upwardly to rock the arm 31 clockwise and produce downward movement of valve 26.

A rocker arm bracket 40 includes a tubular yoke 41 connected at its ends with feet 42 and 43 and at its intermediate portion with a foot portion 44. The feet 42, 43 and 44 support the rod 32 which is secured by a screw 45 threaded into the foot 44. The feet 42 and 43 are attached by means of bolts 46 and 47 to posts 48 and 49, respectively, extending from the superstructure 23. Springs 50 and 51 interposed between adjacent pairs of rocker arms 31 tend to maintain the rocker arms in position and prevent side wise movement thereof.

The foot member 44 is provided with an extension 52 which receives the threaded upper end 53 of a rod 54. The lower end of the post 54 is attached to the crankcase 20. The threaded end 53 receives rats 55 and 56 between which the extension 52 is clamped. The nut 56 is provided with graduations 57 cooperating with an index mark 58 provided on the extension 52. A collar 59 provided on the post 54 limits the downward movement of nut 56.

To adjust the clearance between the parts of the valve operating mechanisms the screws 23 may be turned so that all of the clearance in the mechanism connecting each cam 38 with its corresponding valve 26 may be taken up and the screws then looked in their proper positions by lock nuts 33. Then the clearance between the several rocker arms and the ends of the valve stems 27 when the valves are closed can be adjusted simultaneously by means which includes the adjusting nut 56. The itch of the threaded portion 53 and the gra uations 57 can be such that the turning of the nut 56 one division of the graduations with respect to the index 58 will change the rocker arm clearance .001 of an inch. If a clearance of .002 of an inch is desired the nut 55 is first loosenedand the nut 56 is turned two divisions of the graduations 57 to the right as.

viewed in Fig. 3 causing the nut 56 to be screwed upwardly alon the post 54 to elevate the rod 32 sufiiciently to produce a clearance of .002 of an inch between each rocker arm and its valve when closed. The portion 41 is relativel stiff, and the feet 42 and 43 relatively exible adjacent the pedestals 48 and 49, so bending will take place in feet 42 and 43 rather than in other bracket when .the valve moving the bracket. of clearance of portions of the clearance is adjusted by Therefore the adjustment all the valve mechanisms associated with the the desired clearance is obtained by turning the nut 56 a tions 57. A

As viewed in Fig. 1 the bracket 40 may be considered a beam having one end attached to the head of the cylinder 21 and the other end attached to the crankcase of the engine, and su' porting between its ends the rocker arm ro 32. The pedestals 48 and 49 which provide the connection between the'bracket 40 and the cylinder are substantially the same distance horizontally from the axis of the rod 32 as the stem 27 of valve 26. Therefore the toe portionsof feet 42 and 43 will move upwardly substantially the same distanceas the ends of the valve stems 27 move as the cylindertemperature increases. 1e post 54 is located the same distance from the cylinder as the push rods and is subjected to substantially thesaine variations in temperature as the push rod by reason of its proximity to the cooling fins of the engine. Therefore the portion 52' of bracket will move upwardly a distance substantially equal to the expansion of the push rod 36.

distance determined by gradua- As the engine temperature increases the I bracket will move upwardly in conformity with the expansion of the push rod and with the expansion of the cylinder and valve, and the clearance in the valve mechanism will remain substantially constant.

In case the post 54 is not subjected to the 33. As stated beforecylinders at points upon one same temperature change as the push rod 36, the post 54 can be made of material having a greater coefficient of expansion than i the material of the push rod so that the portion 52 of bracket 40 will move upwardly a dlztance equal to the upward movement of the push rod 36 in expanding.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In combination in an engine crank case, and a plurality of cylinders extending upwardly therefrom; a plurality of valves arranged to control ports leading into and out'from the upper ends ofsaid cylinders; a shaft arranged above said cylinders; a plurality of oscillating rocker arms sup ported by said shaft and whereby said valves are operated; a unitary single piece bracket arranged above and extending along the upper ends of said cylinders and where-- by said shaft is supported, and the two ends of which bracket are supported from said side of said shaft; means for supporting the middle part of said bracket from the crankcase of the engine at one point upon the other side of said shaft; and means for operating said rocker arms. u

2. In combination in an engine having a crankcase, and a plurality of cylinders extending upwardlv therefrom; a plurality of valves for controlling ports leading into an out from the up er ends of said cylinders; a plurality of osci lating rocker arms whereby said valves are operated, and means for oper ating said rocker arms; a unitary single iece bracket arranged above and extending along the upper ends of said cylinders and whereby the rocker arms aforesaid are pivot? ally supported; two pedestals extending upward from the upper ends of -said cylinders and whereby the two ends 50f said bracket are supported at points to one side of the pivotal supports for said rocker arms; and a third pedestal extending upward from the crankcase of the engine and whereby the middle part of said bracket is supported at a single point located to the other side of the pivotal supports for said rocker arms.

In testimony whereof I hereto aflix' my signature. 1 t .l

onanLns'F. KETTERING.

having a 

